Preheat oven to 350ºF. Spray a 9x13-inch baking dish with nonstick cooking spray.

Stir together softened butter and cream cheese in a large bowl. Add cream of chicken soup, shredded chicken, cooked rice, garlic cloves, Italian dressing mix, ½ cup shredded cheese, and chicken stock to the bowl and stir to combine.

Pour the rice mixture into the prepared casserole dish. Top with remaining 1½ cups shredded cheese.

Cover the pan with aluminum foil and bake for 25 minutes. Remove the foil and bake for an additional 15 minutes or until bubbly and the cheese is melted. Garnish with fresh parsley.